Author of

• 20173

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  P2.09 - Mesothelioma (ID 710)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Mesothelioma
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 23454

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    P2.09-008 - Usefulness of Immunohistochemistry in the Differential Diagnosis of Epithelioid Mesothelioma and Lung Squamous Cell Carcinoma (ID 9268)

    09:30 - 09:30  |  Author(s): Y. Katayama
    • Abstract
    • Slides

    Background:
    The differential diagnosis between epithelioid mesothelioma (EM) showing a solid histological pattern (solid EM) and poorly differentiated squamous cell carcinoma (SCC) can be challenging with conventional light microscopy (haematoxylin and eosin-stained specimen) alone. The role of immunohistochemistry in distinguishing pleural EM from lung adenocarcinoma (LAC) has received much attention. Currently, many immunohistochemical markers are available for distinguishing pleural EM from LAC. . However, there are only a few reports on the immunohistochemical differential diagnosis of EM and lung SCC. Ordonez et al. have reported the immunohistochemical analyses of 30 EMs showing a solid pattern and 30 pulmonary non-keratinizing SCCs, and have recommended the combination of two positive (Wilms' tumour gene product; WT1 and calretinin/mesothelin) and two negative (p63 and Epithelial-related antigen; MOC31) markers for differentiating EM from lung SCC. The aims of this study were to clarify the usefulness of immunohistochemistry in the differential diagnosis of solid EM and poorly differentiated SCC, and to confirm the validity of a specific type of antibody panel. Additio nally, we aimed to clarify the pitfalls of immunohistochemical analyses.
    
    Method:
    Formalin-fixed paraffin-embedded specimens from 36 cases of solid EM and 38 cases of poorly differentiated SCC were immunohistochemically examined for calretinin, podoplanin (D2-40), WT1, cytokeratin (CK) 5/6, p40, p63, carcinoembryonic antigen (CEA), MOC31, claudin-4, thyroid transcription factor-1 (TTF-1), and napsin A.
    
    Result:
    WT1 showed the highest diagnostic accuracy (85.1%) as a mesothelial marker, and CEA, p40 and claudin-4 showed higher diagnostic accurac ies (95.9%, 94.6%, and 93.2%, respectively) as carcinoma markers. Calretinin (diagnostic accuracy: 75.7%), D2-40 (diagnostic accuracy: 67.6%), CK5/6 (diagnostic accuracy: 63.5%), TTF-1 (diagnostic accuracy: 55.4%) and napsin A (diagnostic accuracy: 52.7%) could not differentiate between solid EM and poorly differentiated SCC. Among these markers, the combination of calretinin and WT1 showed the highest diagnostic accuracy (86.5%) as a positive marker, and the combination of p40 and CEA showed the highest diagnostic accuracy (97.3%) as a negative marker. The combin ation of CEA and claudin-4 also showed relatively high diagnostic accuracy (94.6%) as a negative marker.
    
    Conclusion:
    We recommend the combination of WT1 and calretinin as a positive maker, and the combination of CEA and claudin-4 as a negative marker, for diff erential diagnoses of solid EM and poorly differentiated SCC.
    
    

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